Cooled Laser Fiber And Method For Improved Thermal Therapy

ABSTRACT

In one embodiment, the disclosure is directed to an integrated apparatus for delivering energy to a tissue. The integrated apparatus included a housing having a distal end and a tubular structure located within the housing forming a first annulus between the tubular structure and the housing. The tubular structure is configured to accept an energy delivery component and is configured to form a second annulus between the tubular structure and the energy delivery component. The first annulus and the second annulus are configured to communicate with each other proximate to the distal end of the housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/508,050 filed on Oct. 7, 2014, which is a continuation of U.S. patentapplication Ser. No. 13/493,699 filed on Jun. 11, 2012, now U.S. Pat.No. 8,851,080 issued on Oct. 7, 2014, which is a continuation of U.S.patent application Ser. No. 11/749,854 filed on May 17, 2007, now U.S.Pat. No. 8,211,095 issued on Jul. 3, 2012, which is acontinuation-in-part of U.S. patent application Ser. No. 10/703,304filed on Nov. 7, 2003, now U.S. Pat. No. 7,270,656 issued on Sep. 18,2007. The entire disclosures of each of the above applications areincorporated herein by reference.

FIELD

This disclosure, in general, relates to energy delivery apparatuses,energy delivery systems, and methods for using same.

BACKGROUND

Laser interstitial thermal therapy (LITT) is a clinical tool fortreating various malignant tumors in the liver, brain, ENT, or abdominallocations, as well as for treating benign alterations, such as prostateadenomas. Fiber optics that terminate in either bare fibers or diffusingapplicators are punctured into the pathological volume to deliver thelaser energy within the desired region of treatment. After positioningof the fibers, target tissues are irradiated causing volumetric heatingthat leads to thermal tissue necrosis. Tumor destruction with directheating is therefore possible, while greatly limiting side effects oradditional damage to surrounding structures. Furthermore, such thermalmethods are associated with faster recovery than conventional surgicalresection procedures.

Large applicators may cause trauma to healthy tissue when accessing thepathological volume. Applicators where light distribution results inhigh power density and heat generation, exceeding the thermal diffusioninto the tissue can cause areas close to the applicator to char andpotentially vaporize. Charring limits heat deposition within deepertissue volumes due to increased absorption of light energy. As charredtissue continues to absorb incident light, its temperature continues torise, leading to carbonization around the applicator. Furthercoagulation of deeper layers is dependent on heat conduction away fromthis carbonized volume.

While it is indeed possible to create large thermal lesions in thismanner, the morphology of the resulting lesion is undesirable.Furthermore, high temperatures associated with the carbonized tissueoften result in failure of the applicator tip and fiber optic withsignificant attendant risk for patients. As such, an applicator thatlimits charring and vaporization would be desirable.

Typical applicators are multi-component applicators. Proceduresutilizing these applicators involve multiple insertion steps and timeconsuming actions taken by the medical professional performing theprocedure. Such steps and actions prolong the surgical process andendanger the patient. In addition, multiple insertion steps potentiallycause slippage of catheters and additional damage to surrounding tissue.As such, an improved applicator would be desirable.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

[Insert Summary Description]

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1A is a block diagram and plan view of an exemplary energy deliveryapparatus in accordance with an embodiment of the disclosures madeherein.

FIG. 1B is a partial fragmentary side view depicting an embodiment of adistal portion of the energy delivery apparatus depicted in FIG. 1A.

FIG. 1C is a partial fragmentary side view depicting an embodimentwherein the energy delivery component includes a diffusing tip element.

FIG. 1D is a partial fragmentary side view depicting an embodimentwherein the energy delivery component has a bare tip optical waveguide.

FIG. 1E is a partial fragmentary side view depicting an embodimentwherein the energy delivery component includes a diffusing tip elementwith reflective means for selective angular energy emission.

FIG. 1F is a cross sectional view depicting an embodiment of a distalsection of the energy delivery apparatus.

FIG. 1G is a cross sectional view depicting an alternative embodiment ofa distal section of the energy delivery apparatus with means formaintaining consistent lumen dimensions during use.

FIG. 1H is a partial fragmentary side view depicting an embodiment of aproximal portion of the energy delivery apparatus depicted in FIG. 1A.

FIG. 1I is a schematic diagram illustrating an embodiment of an energydelivery apparatus.

FIG. 2A is a diagrammatic view depicting an embodiment of a method oftreatment with an energy delivery apparatus of a Cooled Laser Fiber(CLF) system.

FIG. 2B is a diagrammatic view depicting an exemplary embodiment of amethod of treatment with an energy delivery apparatus of a CLF system.

FIG. 3A is a partial fragmentary side view depicting an embodiment of adistal portion of the energy delivery apparatus depicted in FIG. 1Ahaving embedded scattering centers in the distal tip.

FIG. 3B is a partial fragmentary side view depicting an embodiment of adistal portion of the energy delivery apparatus depicted in FIG. 1Ahaving reflective means at the distal tip.

FIG. 3C is a partial fragmentary side view depicting an embodiment of adistal portion of the energy delivery apparatus depicted in FIG. 1A withmeans for perfusing tissue adjacent to the energy delivery apparatus.

FIG. 3D is a partial fragmentary side view depicting an embodiment of adistal portion of the energy delivery apparatus depicted in FIG. 1A thatallows infusion of fluids through the distal tip by retraction of thediffusing tip optical waveguide

FIG. 3E is a partial fragmentary side view depicting an embodiment of adistal portion of the energy delivery apparatus depicted in FIG. 1Ahaving an optically transmissive coating that provides a non-sticksurface.

FIG. 3F is a partial fragmentary side view depicting an embodiment of adistal portion of the energy delivery apparatus depicted in FIG. 1Ahaving a stepped down diameter at the distal end of the energy deliveryapparatus.

FIGS. 3G-3J are partial fragmentary isometric views depictingembodiments of outer housing and tubular structures of the energydelivery apparatus depicted in FIG. 1A with reflective materials usedfor selective angular energy emission.

FIG. 4A-4G are cross sectional views depicting alternative embodimentsof a distal section of the energy delivery apparatus.

FIGS. 5-7 are flow diagrams depicting exemplary methods for use of theapparatus.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

Energy delivery systems, such as Cooled Laser Fiber (CLF) systems, maybe used to treat tissue within a patient. For example, a CLF system maybe used to treat diseased tissues such as malignant and benign tumorsand adenomas. In one exemplary embodiment, an energy delivery apparatusis inserted into the tissue, laser energy is dispersed within thetissue, and as a result, thermal necrosis occurs. The CLF system may beutilized to facilitate thermal coagulation of tissue, and moreparticularly to treat solid cancerous tumors in soft tissue, such ashuman and animal tissue.

FIGS. 1A-1H depict embodiments of an exemplary energy delivery apparatusof a Cooled Laser Fiber (CLF) system. As illustrated in FIG. 1A, the CLFsystem includes an energy delivery apparatus 1, an energy deliverycomponent 2, an energy source 4, and a cooling media supply apparatus 6.The proximal end of the energy delivery component 2, is coupled to theoutput of the energy source 4. The distal end 3 of the energy deliverycomponent 2, extends within the energy delivery apparatus 1. The coolingmedium supply apparatus 6 is connected to the inlet fluid port 8 of theenergy delivery apparatus 1. The outlet fluid port 10 is eitherconnected back to the cooling medium supply apparatus 6 (recirculatingsystem) or to a suitable waste collection area (non-recirculatingsystem).

In the exemplary embodiment depicted, the energy delivery apparatus 1includes a housing 12 attached to a coupling assembly 26. A structure 16separates the lumen of housing 12 into two channels. A first channel 20is formed between the structure 16 and the housing 12 and a secondchannel 18 is formed between the energy delivery component 2 and thestructure 16. The channels 18 and 20 communicate near or proximate thedistal end of the housing 12 to allow fluid to pass from one channel tothe other. The channels 18 and 20 may be isolated proximate the couplingassembly to allow fluid to, for example, enter port 8, flow throughchannel 18, return through channel 20, and exit via the outlet port 10.However, in other embodiments, the fluid may flow in the oppositedirection. In this manner, counter current cooling fluid flow cools thehousing 12, the structure 16, the energy delivery component 2, and thesurrounding tissue. In the above exemplary embodiment, the structure 16is depicted as tubular and the channels 18 and 20 are depicted asannuluses or concentric flow paths. However, various shaped structures16 or shaped housings 12 may be used to form channels. As such, thetube-like structures, 12 and 16, may have cross-sectional shapes such asstars, squares, triangles, ovals, circles, and other shapes.

In one exemplary embodiment, the energy delivery apparatus 1 and theenergy delivery component 2 are integrated or assembled just prior toinsertion into the tissue. In another exemplary embodiment, the energydelivery apparatus 1 and the energy delivery component 2 are integratedor assembled during manufacture prior to being delivered for use.

Referring to FIGS. 1B through 1E, energy delivery apparatus 1 includes aflexible outer housing 12 having a tubular structure along its lengthand a penetrating tip 14 at its distal end. The outer housing 12 may,for example, be rigid enough to penetrate soft tissue without kinking,yet be flexible enough to follow curved or arcuate paths. The solidpenetrating tip 14 may take the form of a cutting edge or a point, amongothers. The housing 12 contains an inner tubular structure 16 within itslumen that extends between a proximal end and a distal end of the outerhousing 12. The inner tubular structure 16 may be centered within thehousing 12 to create fluid inlet lumen 18, and fluid outlet lumen 20.The inlet and outlet lumens (18 and 20) facilitate delivery and returnof cooling media (e.g. water, saline, or carbon dioxide, among others)to and from the distal end of the energy delivery apparatus 1. The fluidinlet lumen 18 facilitates housing of the energy delivery component 2.Suitable materials for the flexible outer housing 12, and inner tubularstructure 16 include flexible radio-opaque and non radio-opaque medicalgrade plastic tubing, such as polycarbonate (Makrolon, Bayer Polymers),polyurethane, polyethylene, polypropylene, silicone, nylon,polyvinylchloride (PVC), polyethylene terephthalate (PET),polytetrafluoroethylene (PTFE), acrylonitrile butadiene styrene (ABS),polyether sulphone (PES), polyetheretherketone (PEEK), fluorinatedethylene propylene (FEP), other biocompatible polymers, or anycombination thereof.

In one particular embodiment, the inner diameter of the inner tubularstructure 16 may range from 0.6 mm to 2.0 mm, such as between 0.9 mm and1.1 mm. The outer diameter of the inner tubular structure 16 may rangefrom 0.7 mm to 2.1 mm, such as between 1.0 mm to 1.2 mm. The innerdiameter of the outer housing may range from 1.0 mm to 1.9 m, such asbetween 1.2 mm and 1.4 mm, and the outer diameter of the outer housingmay range from 1.2 mm to 2.5 mm, such as between 1.3 mm and 1.6 mm orless than 1.5 mm. For example, in a preferred embodiment in which a 0.4mm core diameter fiber optic is used as the energy delivery component,and which is further provided with a buffer jacket of 0.730 mm outerdiameter (OD), the inner tubular structure 16 is preferably 1.09 mm IDand 1.17 mm OD, and the outer housing is preferably 1.37 mm ID and 1.57mm OD. Prefabrication or integration permits smaller diameters, whichcause less peripheral tissue damage and may be easier to guide throughtissue.

The energy delivery component 2 disposed within the fluid inlet lumenincludes one or more optical waveguides positioned to direct lightthrough both the inner tubular structure 16 and outer housing 12. In aparticular embodiment, the energy delivery component 2 may be movablerelative to the energy delivery apparatus 1, for example, translatingalong the axis of the energy delivery apparatus 1. Energy emitted from adiffusing tip of the energy delivery component 2 may pass throughtransparent housing 12 and structure 16. More than one region of tissuelocated along the housing 12 may be treated by moving the energydelivery component 2.

In at least one embodiment, the distal end 3 of the energy deliverycomponent 2 preferably consists of an optical waveguide terminated witha diffusing tip element 9, as illustrated in FIG. 1C. The diffusing tipelement 9 is designed to emit light 19 in a uniform cylindrical patternaround the center axis of the waveguide. In at least one embodiment, thewaveguide is an optical fiber with core 5, cladding 11, and protectivejacket 7. In an alternative embodiment illustrated in FIG. 1D, energydelivery component 2 may consist of a bare tipped optical waveguide inwhich the distal end of the optical waveguide is polished flat resultingin a forward propagation of emitted energy 19. In yet anotheralternative embodiment, energy delivery component 2 may consist of anoptical waveguide terminated with a selective angular emitting element15, as illustrated in FIG. 1E. The angular emitting element 15 may beconstructed by placing a reflective material 17 over a section of adiffusing tip element 9 thereby preventing significant energy frompassing through that section of the element. Suitable materials for thereflective material 17 include polished surfaces of gold, silver,aluminum, and other reflective materials. In one exemplary embodiment,the energy delivery component 2 may be rotated to direct photons 19emitted from the angular emitting element 15.

A cross section of a distal portion of an energy delivery apparatus 1 isillustrated in FIG. 1F. In at least one embodiment, the fluid inletlumen 18 is defined by the space between the energy delivery component 2and the inner wall of the inner tubular structure 16. The fluid outletlumen 20 is defined by the space between the outer wall of the innertubular structure 16 and the inner wall of the outer tubular housing 12.In alternative embodiments, the cross-sectional shape of the energydelivery apparatus may take forms such as a circle, triangle,star-shape, and oval, among others. In further embodiments, the outerhousing may be shaped to form separate channels. In another exemplaryembodiment, the structure 16 may be corrugated to provide channels. Theouter surface of housing 12 may be shaped to increase heat transfersurface area.

A cross section of an alternative embodiment of the energy deliveryapparatus 1 is illustrated in FIG. 1G. In one embodiment, energydelivery apparatus 1 may include one or more inner spacers 22 locatedbetween inner tubular structure 16 and energy delivery component 2 ormay include one or more outer spacers 24 located between inner tubularstructure 16 and outer tubular housing 12. The inner spacers 22 maymaintain a consistent distance between energy delivery component 2 andinner tubular structure 16 around the circumference of energy deliverycomponent 2 such as to maintain consistent lumens or to limit movementof one lumen with respect to the other. Similarly, the purpose of outerspacers 24 is to maintain a consistent distance between inner tubularstructure 16, and outer tubular housing 12 around the circumference ofinner tubular structure 16. It should be noted that inner spacers 22 andouter spacers 24 may extend along the entire length of energy deliveryapparatus 1 or alternatively may only be located along discrete sectionswhere maintaining consistent profiles may be more important such as nearthe distal end 3 of energy delivery component 2. In alternativeembodiments, the structure 16 or the housing 12 may be shaped to formchannels or provide structural integrity for maintaining open lumens.

Referring to FIG. 1H, a coupling assembly 26 is attached at the proximalend 28 of the outer housing 12. The coupling assembly 26 includes theinlet fluid port 8, outlet fluid port 10 and an opening 30 forintroducing an energy delivery component 2. A suitable coupling assemblymay be formed by mating two male-female taper luer tees, such as part#LT878-9, Value Plastics, Inc. A male Touhy Borst connector 32, such aspart#80344 Qosina, may be included to provide a leak-proof seal at theenergy delivery component opening 30 and for securing the energydelivery component 2 to the coupling assembly 26. The distal segment 34of the coupling assembly is bonded to the outer housing 12 to create afluid tight seal. A proximal section 36 of coupling assembly 26 containsa seal 38 between the inner tubular structure 16 and the proximalsection 36 to prevent fluid communication between inlet fluid port 8 andoutlet fluid port 10 within the coupling assembly 26. Both distal andproximal seals and other bonds may be created using a suitable UV cureepoxy, such as Part#140-M, Dymax Corp. Alternative methods of bondingand sealing may be used including various cyanoacrylates, epoxies,silicones, heat bonds, press fits, and threaded assemblies, among othermethods. It is contemplated that the opening 30 and one of inlet fluidport 8 or outlet fluid port 10 may be coincident. In an alternativeembodiment, FIG. 1I portrays a schematic of an integrated energydelivery apparatus wherein fluid outlet port 10 and energy deliverycomponent opening 30 mutually comprise one another.

Returning to FIG. 1H, a heat transfer medium supply passage 40 extendsbetween the inlet fluid port 8 and the fluid inlet lumen 18 for enablingflow of heat transfer medium from a heat transfer medium supplyapparatus 6 through the coupling assembly 26 into the fluid inlet lumen18. A heat transfer medium return passage 42 extends between the fluidoutlet port 10 and fluid outlet lumen 20 for enabling flow of heattransfer medium from the fluid outlet lumen 20 through the couplingassembly 26 and out of the energy delivery apparatus 1. The heattransfer medium, for example, may be a cooled medium, a heated medium,or a medium having a temperature different than that of the tissue, suchas a room-temperature medium.

An embodiment of a heat transfer medium supply apparatus may be acirculation type medium supply apparatus or a non-circulation typemedium supply apparatus. In a circulation type medium supply apparatus,heat transfer medium is supplied from a reservoir to the energy deliveryapparatus 1 and back to the reservoir. In a non-circulation type mediumsupply apparatus, heat transfer medium is supplied from a supplyreservoir to the energy delivery apparatus 1 and then to a separatereturn reservoir. An example of a non-circulation type medium apparatussystem includes a syringe pump, wherein a body of a syringe is a supplyreservoir. Benefits of the use of a syringe pump include ease ofmetering the heat transfer medium and reduced potential forcontamination of heat transfer medium being supplied to the circulationchamber. Suitable syringe pumps are commercially available from New EraPump Systems Corporation and from Harvard Apparatus Corporation.

FIG. 2A depicts an embodiment of a method for utilizing the energydelivery apparatus 1 depicted in FIGS. 1A through 1E. The distal portion44 of the energy delivery apparatus 1 is inserted into the tissue 46 ofa patient and directly within the diseased tissue 48. The distal portion44 may be guided into the tissue 46 via a percutaneous approach under aknown guidance approach such as fluoroscopic, MRI, ultrasound, CT,stereotaxis, among others. In one exemplary embodiment, the energydelivery apparatus is inserted through a guide hole or incision. Inanother exemplary embodiment, the energy delivery apparatus may beinserted directly into tissue without an introducer or catheter. Once ata location to be treated, such as within the diseased tissue 48, energyis delivered into the diseased tissue 48 after passing from an energysource 4, through the energy delivery apparatus 2, through the mediumwithin the fluid inlet lumen 18, through the inner tubular structure 16,through the medium within the fluid outlet lumen 20, and through theouter housing 12. In one embodiment, the energy source 4 is a laseroperating at a wavelength between 350 nm and 2100 nm, such as at about980 nm.

During delivery of energy, a cooling medium is introduced into theenergy delivery apparatus 1 such that it flows through the fluid inletlumen 18 around and in contact with the energy delivery component 2. Thecooling medium exits the fluid inlet lumen 18 at the distal end of theinner tubular structure 16 and enters the fluid outlet lumen 20 at thedistal end of the outer housing 12. The cooling medium flows backthrough the energy delivery apparatus 1 and exits the fluid outlet lumen20 at the proximal end of the outer housing 12. During this travel thecooling medium contacts the inner tubular structure 16, the energydelivery component 2 and the outer housing 12, thus cooling the innertubular structure 16, the energy delivery component 2, the outer tubularhousing 12, and tissue 46 in contact with the energy delivery apparatus1. Accordingly, both the tissue under treatment and the energy deliveryapparatus 1 are cooled, minimizing the possibility of damaging energydelivery component 2 and energy delivery apparatus 1, or overheatingadjacent tissue. It should be appreciated that the direction of flowcould be reversed with the inlet flow traveling between the outerhousing 12 and inner tubular structure 16 and the outlet flow travelingthrough the lumen of the inner tubular structure 16. In either method ofoperation, both the energy delivery component 2, and tissue 46 incontact with energy delivery apparatus 1 will experience cooling.

The temperature or flow rate of the cooling medium may be controlled toprovide a desired cooling of tissue or energy delivery component. It iscontemplated herein that the cooling medium may flow in a continuous orin an intermittent manner. Modulating supply temperature or flow rate ofthe cooling medium allows for increased deposition of photon energy byreducing or eliminating damage of tissue in direct contact with energydelivery apparatus 1, thus leading to development of increased possiblelesions sizes.

The heat transfer medium may be a cooling medium or a heating medium.Examples of the cooling medium include room temperature and chilledfluids including liquids and gases such as saline solution, water, air,nitrogen, carbon dioxide, alcohols, and other suitable substances.Suitable substances include fluids with a suitable heat capacity or thatare transmissive to the wavelength of light emitted from the energydelivery component 2. In some embodiments, the fluid may also includesealants, coagulants, anti-coagulants, anesthetics, optical agents,radio-opaque agents, dyes, magnetic resonance agents, therapeutic drugs,and chemotherapy agents, among other treatment agents.

In one exemplary embodiment, a fluid containing an MRI contrast agentmay be used during insertion of the energy delivery apparatus 1. Thecooling fluid may be optionally changed during energy delivery ortherapeutic agents may be added at appropriate times during treatment.

It is contemplated herein that before, during or after the delivery ofenergy, induced temperatures may be monitored using MRI-basedthermometry. Accordingly, procedures may be conducted for facilitatingestimation of thermal damage at the active area of the energy deliveryapparatus 1 and furthermore for preventing overheating of energydelivery apparatus 1, or other tissues in its surrounding area.

Cooling tissue in accordance with embodiments of the disclosures madeherein permits creation of larger thermal lesions in a safer manner.Cooling of the tissue in contact with energy delivery apparatus 1 limitssuch tissue from being charred or carbonized by overheating. By limitingthe formation of carbonized tissue, forward propagation of photons bydirect absorption is not impeded, thus allowing continued lesion growthfrom volumetric heating by deeper penetration of photons prior toabsorption, as opposed to primarily conductive heating as in the case ofcarbonized tissue. Furthermore, there is a reduced potential for theenergy delivery component 2 to overheat and cause damage or destructionof components comprising the energy delivery apparatus 1. Furthermore,cooling tissue near the interface of energy delivery apparatus, wherepower density or induced temperature is highest, means that energy maybe deposited at a higher rate or in greater quantity without reachingundesirable temperature elevation in tissue.

In one exemplary embodiment, energy may be applied at a rate of 8 to 9watts for a period of 3 to 5 minutes. Lesions of greater than 2 cmdiameter may be created quickly in less than 1 minute of treatment,improving the likelihood and efficiency of complete treatment ofcancerous lesions or other tissues. Cooling methods in accordance withthe disclosures maintain energy delivery apparatuses, such as laserapplicators, below threshold temperatures for thermal destruction andproviding removal of surface heat, allowing deeper and longer lastingpenetration of photons in treated tissue.

FIG. 2B depicts one exemplary application for the CLF apparatus. In thisexemplary application, the apparatus is inserted through healthy tissuesuch as brain tissue and into a tumor 49. The distal end of the energydelivery component is located within the tumor 49 and energy istransmitted to the diseased tissue. The cooling medium cools the energydelivery apparatus and tissue in contact with the energy deliveryapparatus. Alternative embodiments may also permit delivery oftherapeutic agents to the diseased tissue.

FIG. 3A depicts an alternative embodiment of the energy deliveryapparatus 1 wherein the penetrating tip portion 14 of the outer housing12 includes a region of light scattering particles 50 embedded withinthe tip for preventing excessive forward propagation of light fromenergy delivery component 2. The region of light scattering is adaptedto allow increased power use while preventing high power densities atthe distal end of the energy delivery apparatus 1 and can also be usedto tailor the shape of the resulting lesion.

FIG. 3B depicts an alternative embodiment of the energy deliveryapparatus 1 wherein a reflective component 52 is included within thedistal end of the outer housing 12. The reflective component 52 preventssignificant forward propagation and increases photon scattering alongthe length of the laser delivery component 2 by causing photons whichexit the distal end of laser delivery component 2 to be reflected backinto the diffusing tip element 3 where their chances for being scatteredout along the length of diffusing tip element 3 and into the tissueincrease. Use of reflective component 52 may also aid in tailoring theresulting energy distribution emitted along the length of energydelivery apparatus 1 and hence the resulting lesion within the tissue.

FIG. 3C depicts an alternative embodiment of the energy deliveryapparatus 1 wherein the outer housing 12 includes perforations 54 alongits length. Perforations 54 may provide increased tissue cooling, oralternatively may be used for administration of anesthetics, therapeuticdrugs, light absorptive agents, agents that alter the optical propertiesof the tissue or other fluids. Alternatively, membranes may beincorporated into the housing to allow agents to pass into the tissue.In alternative embodiments, fluid may be extracted from the tissue fortesting purposes.

FIG. 3D depicts an alternative embodiment of the energy deliveryapparatus 1 wherein the penetrating tip 14 of the outer housing 12 ismodified to include one of more distal fluid pathways 56. The fluidpathway 56 may be optionally opened or closed by retracting or advancingthe energy delivery component 2. The tip of the energy deliverycomponent 2 is designed such that it seals the opening of the distalfluid pathway when advanced into the fluid pathway.

FIG. 3E depicts an alternative embodiment of the energy deliveryapparatus 1 wherein the outer housing 12 is provided with a thinnon-stick coating 58. The coating 58 may include one of a number offluoropolymers or silicones with high temperature handling capabilityand non-stick surface properties with respect to thermally coagulatedtissues. Materials for outer housing 12 can then be chosen based on thedesired stiffness of the energy delivery apparatus 1 while the thincoating 58 of fluoropolymer or silicone provides the ideal surfaceproperties.

FIG. 3F depicts an alternative embodiment of the energy deliveryapparatus 1 wherein the outer housing 12 and inner tubular structure 16are constructed with a stepped down diameter at the distal end of theenergy delivery apparatus 1. Accordingly the resistance to flow of thecooling media can be significantly reduced by shortening the length ofthe energy delivery apparatus that consists of smaller lumen areas forfluid flow. By doing so a significantly smaller diameter for outerhousing 12 at the active site for laser delivery can be created allowingpenetration into tissues with less force and with less trauma tosurrounding normal tissues.

FIGS. 3G-3J depict alternative embodiments in which reflective material17 is placed around a semi circular section of the outer or innersurface of either the outer housing 12 or inner tubular structure 16.Any single or combination of the embodiments depicted may be used topreferentially emit energy over an angular region of energy deliveryapparatus 1.

FIGS. 4A-4F depict cross-sections of exemplary embodiments of integratedenergy apparatuses. FIG. 4A depicts a cross-section of an exemplaryembodiment in which the energy delivery component 2, the structure 16,and the housing 12 form concentric circular channels. FIGS. 4B-4F depictalternative embodiments in which the housing 12 has a shape that isdifferent than the shape of the structure 16. Each of these embodimentsmay provide channels that remain open when the housing 12 or structure16 is flexed. Some embodiments, such as that illustrated in FIG. 4D, mayalso provide improved surface area for heat transfer. In other exemplaryembodiments, the inside cross-sectional shape of the housing 12 maydiffer from the outside cross-sectional shape. FIG. 4G depicts a furtheralternative embodiment in which structure 16 is replaced by structuralelements of the housing that provide for separate channels, 18 and 20,when an energy delivery component 2 is inserted.

FIGS. 5-7 depict exemplary methods for performing treatment. Asillustrated in FIG. 5, the energy delivery apparatus is assembled, asillustrated at 502. For example, the energy delivery component may beinserted into an integrated apparatus that includes the housing,coupling, and tubular structure. The assembly may occur at amanufacturing site or in an operating room just prior to insertion in apatient. This assembly may include insertion of an energy deliverycomponent. The energy delivery component may be coupled to an energysource. The energy delivery apparatus may also be coupled to a heattransfer medium supply. The assembly may occur prior to insertion of theapparatus in the tissue or during manufacturing of the apparatus. Theapparatus may be inserted into the tissue, as illustrated at 504.

FIG. 6 depicts an exemplary treatment method. The energy deliveryapparatus is located proximate to the tissue to be treated, asillustrated at 602. For example, the tissue may be a tumor and thedistal end of the energy delivery apparatus may be located within thetumor or around the tumor. In the exemplary embodiment illustrated inFIG. 2B, once the skull is accessed, the energy delivery apparatus maybe inserted into the soft tissue of the brain without a guide orcatheter. Alternatively, for tough tissues, a guide or catheter may beutilized. Heat transfer medium, such as a coolant, may be provided tothe integrated energy delivery apparatus, as illustrated at 604. Energymay be provided to an energy delivery component for delivery to thetissue, as illustrated at 606. In one exemplary embodiment, a radialdiffusive tip may be located within the tumor and may be used todisperse photons in a 360 degree pattern. In an alternative embodiment,an angular spread of photons may be provided to tissue using a directedtip located outside the tumor. The heat transfer medium may be providedin conjunction with the energy.

FIG. 7 depicts another exemplary treatment method. The energy deliveryapparatus receives a heat transfer medium, as illustrated at 702. Theheat transfer medium, for example, may be a room-temperature salinecoolant. Alternatively, the heat transfer medium may be heated. The heattransfer medium may pass through the two channels of the integratedenergy delivery apparatus. The heat transfer medium is provided from theenergy delivery apparatus, as illustrated at 704. The heat transfermedium may be recirculated or sent to a waste receptacle. Energy may bereceived by the energy delivery apparatus, as illustrated at 706. Theenergy may be received concurrently with the heat transfer medium.

Example

In one exemplary embodiment, a cooled laser applicator in accord withthe disclosure was constructed to house a fiber optic energy deliverycomponent having a diffusing tip, a 400.mu.m fiber optic core, and a700.mu.m outer diameter and to allow circulation of room-temperaturecooling fluid at a rate of approximately 15 mL/minute. The cooled laserapplicator and internal fiber optic were used in conjunction with a 980nm wavelength laser energy source to produce thermal lesions in volumesof beef myocardium. For comparison, an identical diffusing tip fiberoptic laser applicator was also used without a cooling apparatus.

Using un-cooled diffusing tips, power levels of 6 and 7 W resulted infailure (burning) of the tip before the end of a 5-minute dose period.At 8 W, fiber failure was immediate. In contrast, no failures wereobserved using the cooled diffusing applicator at powers up to 10 W forup to 8 minutes. Further, while significant char resulted in two of theun-cooled lesions, only the largest water-cooled dose resulted in charformation, which was minimal and not in contact with the applicator.Lesion dimensions increased with dose, but for un-cooled fibers, did notincrease with power due to premature tip failure. In the cooled case,lesion dimensions increased monotonically with dose.

While the above exemplary embodiments depict a cooling system andcooling medium, a heating system and heating medium may alternatively beused. In general, a heat transfer medium may be used as fluidtransferred through the channels.

Particular embodiments of the integrated apparatus provide advantageoustechnical features. For example, use of an integrated apparatus permitsconstruction of the apparatus with smaller cross-section components andthinner wall structures. In particular, such construction reduces damagetissue surrounding the treated area and permits improved energytransmission beyond that achievable by the state of the art.

Aspects of the disclosure are found in an integrated apparatus fordelivering energy to a tissue. The integrated apparatus includes ahousing having a distal end and a tubular structure located within thehousing forming a first annulus between the tubular structure and thehousing. The tubular structure is configured to accept an energydelivery component and is configured to form a second annulus betweenthe tubular structure and the energy delivery component. The firstannulus and the second annulus are configured to communicate with eachother proximate to the distal end of the housing.

Further aspects of the disclosure are found in an integrated apparatusfor delivering energy to a tissue. The integrated apparatus includes ahousing having a distal end, a coupling assembly, and a tubularstructure. The coupling assembly interfaces with the housing oppositethe distal end. The coupling assembly includes a first fluid access portand a second fluid access port. The first fluid access port isassociated with a first annulus and the second fluid access port isassociated with a second annulus. The coupling assembly includes anopening for introducing an energy delivery component. The tubularstructure is located within the housing, forming the first annulusbetween the tubular structure and the housing. The tubular structure isconfigured to form the second annulus between the tubular structure andthe energy delivery component. The first annulus and the second annulusare configured to communicate with each other proximate to the distalend of the housing.

Additional aspects of the disclosure are found in an energy deliverysystem. The energy delivery system includes an energy source, a heattransfer fluid source and an integrated apparatus. The integratedapparatus includes a housing having a distal end and a tubular structurelocated within the housing forming a first annulus between the tubularstructure and the housing. The tubular structure is configured to acceptan energy delivery component and is configured to form a second annulusbetween the tubular structure and the energy delivery component. Thefirst annulus and the second annulus are configured to communicate witheach other proximate to the distal end of the housing.

Additional aspects of the disclosure are found in an integratedapparatus. The integrated apparatus includes a housing having a distalend having a penetrating portion. The housing is configured to accept awaveguide internal to the housing. The housing includes a first channeland a second channel internal to the housing. The first channel and thesecond channel are configured to communicate with each other proximateto the distal end and isolated from each other proximate to an endopposite the distal end.

Further aspects of the disclosure are found in an integrated apparatusfor delivering energy to a tissue. The integrated apparatus includes ahousing having an energy delivery end, a first channel portion locatedinternal to the housing and configured to direct coolant flow toward theenergy delivery end, and a second channel portion located internal tothe housing and configured to direct coolant flow away from the energydelivery end.

Aspects of the disclosure are also found in a method of interstitialthermal therapy. The method includes receiving a heat transfer medium atan intake portion of an integrated energy delivery apparatus from asource external to the integrated energy delivery apparatus; providingthe heat transfer medium from an output region of the integrated energydelivery apparatus to a destination external to the integrated energydelivery apparatus; and receiving energy at a proximal end of an energydelivery component. The energy delivery component has a distal endinternal to the integrated energy delivery apparatus and terminatesproximate to a distal end of the integrated energy delivery apparatus.

Further aspects of the disclosure are found in a method for deliveringenergy to a tissue. The method includes locating an integrated apparatusproximate to the tissue; providing transfer fluid via the first annulusand the second annulus to exchange heat with the energy deliveryapparatus; and providing energy to the tissue via the energy deliverycomponent. The integrated apparatus includes a housing having a distalend and a tubular structure located within the housing forming a firstannulus between the tubular structure and the housing. The tubularstructure is configured to accept an energy delivery component and isconfigured to form a second annulus between the tubular structure andthe energy delivery component. The first annulus and the second annulusare configured to communicate with each other proximate to the distalend of the housing.

Additional aspects of the disclosure are found in a method of performinginterstitial thermal therapy. The method includes inserting anintegrated energy delivery apparatus into a tissue and delivering energyvia an energy delivery component to the tissue. The integrated energydelivery apparatus includes a housing including a first fluid channelinternal to the housing and a second fluid channel internal to thehousing. The housing is configured to accept an energy deliverycomponent internal to the housing.

Aspects of the disclosure are also found in a method of interstitialthermal therapy. The method includes assembling an integrated energydelivery apparatus and providing the integrated energy deliveryapparatus for insertion into a tissue. The integrated energy deliveryapparatus includes a housing including a first fluid channel internal tothe housing and a second fluid channel internal to the housing. Thehousing is configured to accept an energy delivery component internal tothe housing.

Further aspects of the disclosure are found in an energy deliveryapparatus having an outside diameter less than 1.5 mm.

The above-disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments that fall within thetrue scope of the present invention. Thus, to the maximum extent allowedby law, the scope of the present invention is to be determined by thebroadest permissible interpretation of the following claims and theirequivalents, and shall not be restricted or limited by the foregoingdetailed description.

What is claimed is:
 1. An apparatus for delivering energy to a tissue,the apparatus comprising: a housing extending from a proximal end to adistal end and defining a lumen therein; an energy delivery componentpositioned within the lumen; a first channel formed adjacent to theenergy delivery component; a second channel formed adjacent to thehousing; a first inlet in communication with the first channel; and asecond outlet in communication with the second channel; wherein a fluidflow path enables a heat transfer fluid to flow from the first inlet tothe first channel, along the second channel to the second outlet totransfer heat from the energy delivery component.
 2. The apparatus ofclaim 1, wherein the energy delivery component is an optical wave guideconfigured to emit energy from a diffusing tip of the energy deliverycomponent.
 3. The apparatus of claim 2, further comprising an energysource coupled to the energy delivery component, wherein the energysource is a laser.
 4. The apparatus of claim 1, wherein the housingfurther includes a structure positioned within the housing thatseparates the first channel from the second channel.
 5. The apparatus ofclaim 4, wherein the structure has a first cross-sectional shape and thehousing has a second cross-sectional shape, wherein the firstcross-sectional shape differs from the second cross-sectional shape. 6.The apparatus of claim 5, wherein the first cross-sectional shape iscircular and the second cross-sectional shape is selected from the groupconsisting of circular, pentagon, triangular, star, rectangular, andoval.
 7. The apparatus of claim 1, wherein the first channel and thesecond channel have a first cross-sectional area adjacent the proximalend of the housing and a second cross-sectional area adjacent the distalend of the housing, the first cross-sectional area is larger than thesecond cross-sectional area.
 8. The apparatus of claim 1, wherein thedistal end of the housing defines a fluid pathway and wherein the energydelivery component is configured to be advanced or retracted in thehousing to close or open the fluid pathway.
 9. The apparatus of claim 1,wherein the housing is flexible and transparent to enable the energydelivery component to deliver energy through the housing.
 10. Theapparatus of claim 1, wherein the housing includes an outer non-stickcoating formed from fluoropolymers or silicones.
 11. The apparatus ofclaim 1, wherein the distal end of the housing includes a penetratingtip portion having an embedded light-scattering particle portion withinthe tip portion for reducing forward propagation of light from theenergy delivery component.
 12. The apparatus of claim 1, wherein thedistal end of the housing includes a penetrating tip and wherein areflective component is positioned within the distal end of the housingadjacent the penetrating tip to reduce forward propagation of energyfrom the energy delivery component.
 13. The apparatus of claim 1,wherein the housing defines a plurality of perforations adjacent thedistal end of the housing to allow fluid to pass from the housing to thetissue.
 14. The apparatus of claim 1, further comprising a reflectivematerial positioned along a length of the housing to direct energy fromthe energy delivery component.
 15. The apparatus of claim 14, whereinthe reflective material is positioned around a portion of the housingalong the length and located either on an inner surface of the housingor an outer surface of the housing.
 16. The apparatus of claim 4,further comprising at least one radially extending spacer extendingbetween the energy delivery component and the structure or the structureand the housing.
 17. The apparatus of claim 2, wherein the optical waveguide is formed as an optical fiber having a core, an outer cladding,and an outer protective jacket.
 18. The apparatus of claim 2, whereinthe optical wave guide includes an angular emitting element positionedover a portion of the diffusing tip to angularly direct energy deliveredfrom the diffusing tip.
 19. The apparatus of claim 1, further comprisinga coupling assembly coupled to the proximal end of the housing anddefining the first inlet and the second outlet and configured to receivethe energy delivery component.
 20. The apparatus of claim 1, furthercomprising a laser energy source to deliver energy to the energydelivery component and a heat transfer fluid supply to deliver the heattransfer fluid through the fluid flow path.
 21. An apparatus fordelivering energy to a tissue, the apparatus comprising: a housingextending from a proximal end to a distal end and defining a lumentherein; a penetrating tip extending from the distal end of the housing;a coupling assembly coupled to the proximal end of the housing, thecoupling assembly defining a first inlet and a second inlet; an opticalwave guide positioned within the lumen to deliver energy; a firstchannel formed adjacent to the optical wave guide; a second channelformed adjacent to the housing; wherein a fluid flow path enables a heattransfer fluid to flow from the first inlet to the first channel, alongthe second channel to the second outlet to transfer heat generated fromthe energy from the optical wave guide.
 22. The apparatus of claim 21,further comprising a laser energy source to deliver energy to theoptical wave guide and a heat transfer fluid supply to deliver the heattransfer fluid through the fluid flow path.
 23. An apparatus fordelivering energy to a tissue, the apparatus comprising: a housingextending from a proximal end to a distal end and defining a lumentherein; a structure positioned within the housing and concentric with alongitudinal axis of the housing; a penetrating tip extending from thedistal end of the housing; a coupling assembly coupled to the proximalend of the housing, the coupling assembly defining a first inlet and asecond inlet; an optical wave guide positioned within the lumen todeliver energy, the optical wave guide extending along the longitudinalaxis of the housing; a first channel formed between the optical waveguide and the structure; a second channel formed between the structureand the housing; wherein a fluid flow path enables a heat transfer fluidto flow from the first inlet to the first channel, along the secondchannel to the second outlet to transfer heat generated from the energyfrom the optical wave guide.
 24. The apparatus of claim 23, furthercomprising a laser energy source to deliver energy to the optical waveguide and a heat transfer fluid supply to deliver the heat transferfluid through the fluid flow path.